text: #ifndef __TIMING_H__
  #define __TIMING_H__
  
  #include <sys/time.h>
  
  void time_measure_start(struct timeval *tv);
  void time_measure_end(struct timeval *tv);
  
  /* tvsub: ret = x - y. */
  static inline void tvsub(struct timeval *x,
  						 struct timeval *y,
  						 struct timeval *ret)
  {
  	ret->tv_sec = x->tv_sec - y->tv_sec;
  	ret->tv_usec = x->tv_usec - y->tv_usec;
  	if (ret->tv_usec < 0) {
  		ret->tv_sec--;
  		ret->tv_usec += 1000000;
  	}
  }
  
  #endif
  